Yes, ants are ectotherms or cold-blooded. This means that they can’t regulate body temperature internally. Instead, they have to rely on external environmental sources like sunlight for thermoregulation.
In this article, we’ll learn more about ants as ectotherms as we discuss the following:
- Why ants are cold-blooded
- How ants thermoregulate
- Why ants thermoregulate
- How temperature affects ants
Why are Ants Cold-Blooded?
Ants are cold-blooded because their internal physiological sources of heat are limited. While they do produce body heat, they can’t maintain or regulate it.
For example, unlike humans, ants can’t burn calories to raise their body temperature. They also can’t subconsciously moderate temperature by means of shivering, sweating, or panting. 
How Do Ants Thermoregulate?
Since ants can’t thermoregulate internally, they have to rely on external sources of heat. As smart as ants are, they have developed several strategies for thermoregulation.
There is, of course, the very basic sunning or seeking warm shelter. During the winter they take refuge under heat collectors like rocks or tree barks for warmth. They’ll also optimize their nests for heating by burrowing deeper underground.
In the same light, ants stay cool by keeping away from the sun. During hot periods, they usually just stay in their nests. There they wait for cooler temperatures before they emerge and start foraging.
Some ants have also been observed to use complex nesting strategies for thermoregulation.
Red wood ants, for example, use insulating materials to build their nests. They then maintain the temperature through the metabolic heat produced by workers. They also create tunnels and passages in the nest for ventilation. 
Why Do Ants Need To Thermoregulate?
Temperature directly affects the metabolism of cold-blooded animals like ants. It plays an important role in their ability to function. By maintaining an ideal temperature, they can move, grow and reproduce normally.
What is the Ideal Body Temperature for Ants?
The ideal temperature for ants is around 75 to 95 degrees Fahrenheit (23 to 35°C) depending on the species. Temperatures above or below this can cause negative physiological changes in ants.
Do Ants Get Cold?
Yes, ants get cold. Ants slow down noticeably during the cold season. In fact, some species become dormant and enter a hibernation-like state called diapause.
Diapause is a biological strategy that ants use to survive unideal conditions. During this state, they become immobile and they stop all activities
See this article to learn more about ant diapause.
Can Ants Survive Cold Temperatures?
Yes, ants can survive cold temperatures. In fact, ants capable of diapause are essentially experts in overwintering.
These ants make sure to prepare well before the cold season. They eat a lot during autumn and build up their fat stores. They also optimize their nests for heating. They dig deeper underground or take shelter under heat collectors like rocks.
Can Ants Freeze to Death?
Yes, ants can freeze to death. Some ants that live in temperate climates are not capable of overwintering. Instead of entering diapause, they enter a cold coma which often leads to death.
Do Ants Get Hot?
Yes, ants also get hot. Studies show that a slight increase in temperature can cause disorientation in ants. Higher temperatures will also render them immobile.
In some cases, extreme heat lead to denaturation. This can cause a disruption in cell activity and cell death. Worst case, ants may overheat and die. 
Ant Behavior and Temperature
Temperature can also alter ant behavior. For instance, harvester ants adjust their foraging behavior depending on temperature. They flip-flop between being diurnal or nocturnal to avoid the cold or the summer heat.
Are Ants Attracted to Heat?
Barring the extremes, yes ants are attracted to heat. Ants are attracted to whatever helps them survive and as cold-blooded animals, they rely on heat to function.
To summarize, ants are cold-blooded animals. They are not capable of regulating their body temperature. Instead, they have to rely on external sources. They thermoregulate by staying under the sun or seeking shade.
They are also directly affected by changes in external temperature. Extreme cold or heat can cause physiological and behavioral changes in ants.
The cold, for example, can cause ants to enter a state of dormancy. On the hand, heat can disorient and render them immobile. Both have been shown to cause changes in ant foraging behavior.